Low-leakage cryogenic emergency shut-off valve

Abstract

The utility model discloses a low leakage's low temperature emergency stop valve, including both sides connection with the connecting end's valve body, the valve ball is arranged in the valve body, the top of valve ball is provided with valve stem, and the outer sleeve of extension is equipped with independent packing gland, and the valve body, extension sleeve, independent packing gland are connected in proper order, and the top of independent packing gland is installed with fireproof blocking mechanism, and the top of fireproof blocking mechanism is installed with single -action pneumatic actuator, and the fusible plug protection cover is installed on single -action pneumatic actuator, and the bottom of independent packing gland is equipped with sealing ring between the top of extension sleeve, the valve stem in independent packing gland is successively sleeved with valve stem seal, elastic rubber seal, sealing gland, packing, packing gland, spring washer, gland nut, stop cover from below to top. The utility model maintenance efficiency is improved significantly, and the sealing performance is further enhanced, and the full life cycle cost advantage is obvious.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, and in particular to a low-leakage cryogenic emergency shut-off valve. Background Technology

[0002] As a core safety component in cryogenic media storage and transportation systems, cryogenic emergency shut-off valves play a crucial role in rapidly cutting off flow paths and containing the spread of accidents in unexpected situations such as leaks, fires, or system overpressure. Because the working medium is often at extremely low temperatures, the valve must maintain reliable sealing, structural integrity, and operational response speed under prolonged cryogenic conditions. This places stringent requirements on valve body materials, sealing methods, and overall construction.

[0003] Currently, most cryogenic valves (including emergency shut-off valves) in the industry employ an extended sleeve structure to address the challenges of cryogenic temperatures. This structure, by placing an extended sleeve between the valve body and the upper actuator, primarily achieves two goals: first, it increases the axial distance between the valve stem stuffing box and the cryogenic valve body, reducing the conduction of cold energy to the packing area; second, it ensures that the neck flange is within the ambient temperature range, preventing seal failure or material damage due to cryogenic brittleness. However, this long-neck structure still has several significant shortcomings in practical applications. The sealing stuffing box at the top is usually an integral design with the sleeve and cannot be disassembled separately. This traditional solution presents the following problems: 1. Limited low-temperature insulation effect: Although the sleeve has a certain length, extremely low temperatures will still gradually rise along the valve stem and sleeve, resulting in excessively low temperatures in the packing area. Under cryogenic conditions or during long-term operation, the packing is prone to hardening, shrinkage, or loss of elasticity, which in turn leads to a decrease in sealing performance and the risk of external leakage.

[0004] 2. Complex and difficult maintenance: When the packing wears out or needs to be replaced, the entire sleeve and its connected actuators and other upper components must be disassembled. This process is not only cumbersome and time-consuming, but it can also damage the valve's insulation layer, leading to prolonged system downtime and significantly increased maintenance costs.

[0005] 3. Rigid configuration leads to poor economy: Because the stuffing box and sleeve are an integral structure, damage to any sealing element often requires replacement of the entire neck assembly, rather than just replacing the low-cost stuffing ring. This design lacks maintenance flexibility and also increases the total life-cycle cost.

[0006] Meanwhile, in certain fields (such as chemical and energy sectors, precision manufacturing and pharmaceuticals), even minute leaks can lead to product contamination or process failure, and may also cause dangers such as explosions. With the increasing stringency of global environmental standards (such as ISO 15848, TA-Luft, etc.), the leakage rate of industrial valves is strictly limited. The sealing performance of traditional ball valves is difficult to meet the new regulations, making low-leakage design a popular demand in the industry. Utility Model Content

[0007] To solve the above problems, this utility model provides a low-leakage, low-temperature emergency shut-off valve.

[0008] To solve the above-mentioned technical problems, the technical solution of this utility model is: a low-leakage cryogenic emergency shut-off valve, comprising a valve body with connecting ends on both sides, a valve ball disposed in the valve body, a valve stem disposed on the top of the valve ball, an extension sleeve and an independent stuffing box fitted on the valve stem, the valve body, the extension sleeve and the independent stuffing box being connected in sequence, a fireproof shut-off mechanism being installed on the top of the independent stuffing box, a single-acting pneumatic actuator being installed on the top of the fireproof shut-off mechanism, a fusible plug and a fusible plug protective cover being installed on the single-acting pneumatic actuator, a sealing ring being provided between the bottom of the independent stuffing box and the top of the extension sleeve; the valve stem inside the independent stuffing box is fitted with, from bottom to top, a valve stem seal, an elastic rubber seal, a sealing gland, packing, a packing gland, a spring washer, a gland nut and a stop cover.

[0009] Furthermore, the top of the valve body is connected to the bottom of the extension sleeve by bolts.

[0010] Furthermore, the valve body has connecting ends bolted to both sides.

[0011] Furthermore, the bottom of the connecting rod inside the fire-prevention mechanism is connected to the top of the valve stem, and the top of the connecting rod is inserted into the center slot of the cylinder of the single-acting pneumatic actuator.

[0012] Furthermore, an extension sleeve is installed at the bottom of the independent stuffing box via connecting bolt two, and a fireproof blocking mechanism is installed at the top of the independent stuffing box via connecting bolt one.

[0013] Furthermore, there are two sets of packing and packing glands.

[0014] Furthermore, there are two spring washers.

[0015] Furthermore, the gland nut is threadedly connected to the valve stem.

[0016] Furthermore, the stop cap is located outside the pressure cap nut.

[0017] Furthermore, the single-acting pneumatic actuator is connected to the air compressor via pneumatic piping.

[0018] The beneficial effects of this utility model are: 1. Significantly Improved Maintenance Efficiency: By adopting an independent stuffing box, when the sealing components need to be replaced or repaired, there is no need to disassemble the extension sleeve structure. Simply loosen the stuffing box cap nut or bolts to remove the individual stuffing box for maintenance. This design significantly shortens maintenance time, reduces system downtime losses, and also reduces the complexity of manual operations and the cost of spare parts.

[0019] 2. Enhanced sealing performance: The independent stuffing box structure provides greater flexibility for optimizing the sealing system. It supports the combination of multiple packing rings, enhancing the multi-stage resistance to media leakage. Simultaneously, the multi-seal structure combining the main seal (packing) and the secondary seal (elastic rubber seal) ensures low leakage performance of the valve, as the secondary seal can compensate for minor wear or leakage in the main seal.

[0020] 3. Significant life-cycle cost advantages: Only the independent stuffing box needs maintenance or replacement, and the neck tube and other components can still be used normally without scrapping, which significantly reduces maintenance and spare parts inventory costs and has better economic efficiency and sustainability. Attached Figure Description

[0021] Figure 1 This is the front view of this utility model; Figure 2 This is a side view of the present invention; Figure 3 This is a top view of an independent stuffing box; Figure 4 This is a bottom view of an independent stuffing box; Figure 5 This is a magnified view of a portion of an independent stuffing box.

[0022] The components are: 1. Single-acting pneumatic actuator; 2. Fireproof blocking mechanism; 3. Independent stuffing box; 4. Extension sleeve; 5. Valve stem; 6. Valve body; 7. Valve ball; 8. Connecting end; 9. Fusible plug; 10. Fusible plug protective cover; 11. Connecting bolt one; 12. Connecting bolt two; 13. Sealing ring; 14. Valve stem seal; 15. Packing; 16. Packing gland; 17. Spring washer; 18. Stop cover; 19. Gland nut; 20. Elastic rubber seal; 21. Sealing gland; 22. Connecting rod. Detailed Implementation

[0023] The following is in conjunction with the appendix Figure 1-5 The technical solution of this utility model has been clearly and completely described. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] A low-leakage cryogenic emergency shut-off valve includes a valve body 6 with connecting ends 8 bolted to both sides. A valve ball 7 is disposed inside the valve body 6, and a valve stem 5 is mounted on top of the valve ball 7. An extension sleeve 4 and an independent stuffing box 3 are fitted around the valve stem 5. The valve body 6, extension sleeve 4, and independent stuffing box 3 are connected in sequence. The top of the valve body 6 is bolted to the bottom of the extension sleeve 4. The bottom of the independent stuffing box 3 is fitted with the extension sleeve 4 via connecting bolt 2 12. A fireproof shut-off mechanism 2 is mounted on the top of the independent stuffing box 3 via connecting bolt 1 11. A single-acting pneumatic actuator 1 is mounted on the top of the fireproof shut-off mechanism 2. The single-acting pneumatic actuator 1 is connected to an air compressor via a pneumatic pipeline. The bottom of the connecting rod 22 inside the fire-prevention mechanism 2 is connected to the top of the valve stem 5. The top of the connecting rod 22 is inserted into the center slot of the cylinder of the single-acting pneumatic actuator 1. The single-acting pneumatic actuator 1 is equipped with a fusible plug 9 and a fusible plug protective cover 10. A sealing ring 13 is provided between the bottom of the independent stuffing box 3 and the top of the extension sleeve 4. The valve stem 5 inside the independent stuffing box 3 is fitted with, from bottom to top, a valve stem seal 14, an elastic rubber seal 20, a sealing gland 21, packing 15, a packing gland 16, a spring washer 17, a gland nut 19, and a stop cover 18. The gland nut 19 is threaded to the valve stem 5, and the stop cover 18 is located outside the gland nut 19. There are two sets of packing 15 and packing gland 16, and two spring washers 17.

[0025] Under normal operating conditions, the air compressor supplies air to the single-acting pneumatic actuator 1 through the pneumatic pipeline. The single-acting pneumatic actuator 1 drives the valve stem 5 to rotate the valve ball 7 through the connecting rod 22, and the low-temperature medium is transported through the connecting ends 8 on both sides of the valve body 6. The extension sleeve 4 blocks the conduction of cold energy. The sealing ring 13 between the independent stuffing box 3 and the extension sleeve 4 seals the connection gap between the two to prevent medium leakage. In addition, the valve stem seal 14, elastic rubber seal 20, and sealing gland 21 in the independent stuffing box 3, together with two sets of packing 15, packing gland 16, and spring gasket 17, form a multi-stage seal. The gland nut 19 is locked and the stop cover 18 is prevented from loosening, so as to achieve low leakage sealing.

[0026] The embodiments described above are merely preferred embodiments of this utility model, and not all feasible embodiments of this utility model. For those skilled in the art, any obvious modifications made without departing from the principles and spirit of this utility model should be considered to be included within the scope of protection of the claims of this utility model. Although this utility model has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of this utility model. In particular, as long as there is no technical conflict, the features in the embodiments disclosed in this utility model can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, this utility model is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A low-leakage cryogenic emergency shut-off valve, characterized in that, The valve body includes a valve body with connecting ends on both sides. A valve ball is located inside the valve body, and a valve stem is located on top of the valve ball. An extension sleeve and an independent stuffing box are fitted around the valve stem. The valve body, extension sleeve, and independent stuffing box are connected in sequence. A fireproof shut-off mechanism is installed on top of the independent stuffing box, and a single-acting pneumatic actuator is installed on top of the fireproof shut-off mechanism. A fusible plug and a fusible plug protective cover are installed on the single-acting pneumatic actuator. A sealing ring is provided between the bottom of the independent stuffing box and the top of the extension sleeve. From bottom to top, the valve stem inside the independent stuffing box is fitted with a valve stem seal, an elastic rubber seal, a sealing gland, packing, a packing gland, a spring washer, a gland nut, and a stop cover.

2. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, The top of the valve body is connected to the bottom of the extension sleeve by bolts.

3. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, The valve body has connecting ends on both sides connected by bolts.

4. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, The bottom of the connecting rod inside the fireproof blocking mechanism is connected to the top of the valve stem, and the top of the connecting rod is inserted into the center slot of the cylinder of the single-acting pneumatic actuator.

5. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, An extension sleeve is installed at the bottom of the independent stuffing box via connecting bolt two, and a fireproof blocking mechanism is installed at the top of the independent stuffing box via connecting bolt one.

6. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, There are two sets of the packing and packing gland.

7. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, There are two spring washers.

8. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, The gland nut is threadedly connected to the valve stem.

9. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, The stop cap is located outside the pressure cap nut.

10. The low-leakage cryogenic emergency shut-off valve according to claim 1, characterized in that, The single-acting pneumatic actuator is connected to the air compressor via a pneumatic pipeline.

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